[Qt-interest] When does QWidget have HWND?

[william lee]

Hi Girish,
I am using win 7, but not touch screen.
Is this problem happen on all win7 machine?
I can test on XP when back to office.

thanks,
William L.

On Fri, Feb 18, 2011 at 7:20 PM, Girish Ramakrishnan
<girish at forwardbias.in>wrote:

> Hi William,
> Which Windows version are you using? Windows 7? Are you aware of
> http://bugreports.qt.nokia.com/browse/QTBUG-14297?
>
> Girish
>
> On Fri, Feb 18, 2011 at 2:03 PM, william lee <welemon at gmail.com> wrote:
> > Hi,
> >
> > I was using spy++ to check Qt application window, sometime I get the HWND
> > for each widget, like button, edit, combo etc. Sometime there isn’t HWND
> for
> > child widget at all.There is only a whole window HWND.
> >
> >
> >
> > For example, Qt 4.6.1.
> >
> > 1.       When you launch qtdemo’s browser project(QtWebKit demo browser),
> > you can use spy++ to check on it, there is only one parent window HWND.
> No
> > child window HWND, like menu bar, toolbar etc.
> >
> > 2.       When you launch qtdemo’s Text Edit project, you can use spy++ to
> > check again, this time you will see every child window has HWND,
> including
> > menu bar, toolbar etc.
> >
> > 3.       Another weird example is qtdemo’s SQL Browser project, when you
> > launch this application, it will pop up a dialog, “Connect…”. This Dialog
> is
> > for adding connections.
> >
> > The first time launch this dialog(when app start, it will auto popup),
> you
> > use spy++ to check on it, there is only one HWND for whole dialog, no
> child
> > HWND.
> >
> > But when you close it, and launch again from File->Add connection…, you
> can
> > use spy++ to check again, now it will have all child widget with HWND…
> >
> >
> >
> > I googled, and find something about alien widget, I read this before. The
> > comments are like:
> >
> > Native Widgets vs Alien Widgets
> >
> > Introduced in Qt 4.4, alien widgets are widgets unknown to the windowing
> > system. They do not have a native window handle associated with them.
> This
> > feature significantly speeds up widget painting, resizing, and removes
> > flicker.
> >
> > Should you require the old behavior with native windows, you can choose
> one
> > of the following options:
> >
> > Use the QT_USE_NATIVE_WINDOWS=1 in your environment.
> > Set the Qt::AA_NativeWindows attribute on your application. All widgets
> will
> > be native widgets.
> > Set the Qt::WA_NativeWindow attribute on widgets: The widget itself and
> all
> > of its ancestors will become native (unless
> Qt::WA_DontCreateNativeAncestors
> > is set).
> > Call QWidget::winId to enforce a native window (this implies 3).
> > Set the Qt::WA_PaintOnScreen attribute to enforce a native window (this
> > implies 3).
> >
> >
> >
> > http://doc.qt.nokia.com/latest/qwidget.html
> >
> >
> >
> > But I didn’t see any relative code in above three projects.  Don’t know
> why
> > there is difference, especially for example 3, the same dialog can have
> > different behavior.
> >
> >
> >
> > Can someone help me to explain it?
> >
> >
> >
> > Thanks!
> >
> >
> >
> > William L.
> >
> > _______________________________________________
> > Qt-interest mailing list
> > Qt-interest at qt.nokia.com
> > http://lists.qt.nokia.com/mailman/listinfo/qt-interest
> >
> >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.qt-project.org/pipermail/qt-interest-old/attachments/20110218/3dc0ee41/attachment.html